According to current studies the number of cardiological diseases is constantly increasing. One typical pathological finding here is so-called ventricular fibrillation or flutter. Abnormalities of pathological origin here cause defective neuron pathways in the ventricle with the result that the heart beats in an uncontrolled manner (too frequently). This is associated with a reduction in the time available to fill the ventricle, so cardiac performance is greatly reduced.
Ventricular fibrillation or flutter gives rise to acute complaints such as chest pain and reduced capability, etc. There is also an increased risk of thrombosis, in turn significantly increasing the likelihood of stroke.
One possible method for treating ventricular fibrillation or flutter is so-called catheter ablation. This method involves the insertion of an ablation catheter into the ventricle, to “burn” or “obliterate” the pathways of pathological origin there. This means that the tissue in this region is modified in such a way that (as scar tissue) it loses its conductivity. There are different options for destroying the tissue. One frequently adopted approach is ablation using high-frequency current, which is transmitted from the catheter tip to the endocardium (inner wall) of the ventricle. There are further options available for ablation, for example cold ablation, etc.
One problem with such ablation methods is that the myocardium or cardiac muscle is not of uniform thickness but its thickness varies locally and with each patient.
For example some patients, perhaps due to more or less intensive sporting activity, have a thinner myocardium, while other patients have a thicker cardiac muscle. Pathologies can also be present, in such a manner for example that where there is stenosis of the coronary arteries certain areas of the myocardium are supplied less efficiently, so the muscle mass reduces locally and the thickness of the myocardium therefore decreases. There are also local differences, with the myocardium being thinner for example at the apical tip of the heart than in the mid-ventricular or basal region.
The catheter output must therefore be varied in order to penetrate the full thickness of the myocardium. If the output is too low, it may be that pathological pathways in the epicardium, in other words in the outer regions of the myocardium, are not reached and the ablation is therefore unsuccessful. If catheter output is too high on the other hand, unnecessary scarring of the myocardial tissue may result and in some instances the pericardium or heart sac may even be damaged.
For these reasons ablation of the left cardiac muscle or myocardium is currently rarely undertaken, as there is a high probability that pathological pathways in the epicardium for example will not be reached. On the other hand ablation—as shown by examples from the treatment of atrial fibrillation or flutter—is fundamentally a better alternative than conservative treatment with drugs and/or pacemaker implantation.
When myocardial ablation is carried out today in the ventricular region, the physician carrying out the procedure does not know the thickness of the myocardium, which varies significantly, specifically in the relevant patient group. It is not possible to identify this thickness in the fluoroscopy image. The physician is therefore only able to use mean values to set the ablation output, with the result that the problems mentioned above arise. It is not possible to ensure optimal setting of output with such an estimation of the thickness of the myocardium and appropriate output.